TECHNICAL FIELD
[0001] The present disclosure relates generally to networking systems and methods and more
particularly to Visible Light Communication (Li-Fi) systems and related Access Points
(AP).
BACKGROUND
[0002] With the explosion of smart phones, tablets, laptops, and other user equipment (UE)
both in enterprise (e.g., bring your own device or BYOD) and guest account scenarios,
there is an ever increasing demand for wireless bandwidth in high density UE environments.
WLAN (also referred to as Wireless Fidelity (WiFi)) has been a primary means of connectivity
for UEs. WLAN is generally defined in IEEE 802.11 and variants thereof. The wireless
spectrum which is necessary for communication between WiFi/WLAN Access Points (APs)
and UEs is becoming increasingly scarce as demand grows exponentially with the proliferation
of such devices.
[0003] Deploying more WiFi/WLAN Access Points (APs) may not be a right solution because
of already high levels of interference from competing devices. Many UEs support communication
modes beyond WiFi, including utilizing subscriber services provided by wireless service
operators with 3G, 4G Long Term Evolution (LTE), and other communication protocols.
Disadvantageously, connectivity through subscriber services can be more costly and/or
may provide lower bandwidth than WiFi. Accordingly, there is a need for alternative
systems and methods to providing wireless bandwidth in high density UE environments.
[0004] Light Fidelity (Li-Fi) communication systems use the visible light portion of the
electromagnetic spectrum for communication between APs and UEs. Li-Fi may also be
referred to as LiFi (Light WiFi). Li-Fi is an alternative to a radio frequency based
communications approach but can also be prone to interference in some environments.
Because Li-Fi signals are limited to line-of-sight and cannot penetrate walls and
closed doors, communication coverage areas provided by Li-Fi APs depends upon the
open space geometry of their rooms and can dynamically change over time as signal
blocking objects are remove and inserted. The resulting potentially small and irregular
geometric coverage areas complicates technical approaches for providing mobility to
users operating Li-Fi UEs.
[0005] EP2953277 discloses a switching method for a visible-light communication terminal device at
an access point.
SUMMARY
[0006] Some embodiments disclosed herein are directed to a coordination node for controlling
communications between Li-Fi APs and UEs. The coordination node is configured to receive
peer connectivity reports from Li-Fi APs which identify Li-Fi APs having at least
partially overlapping coverage areas, and develop a handover pathway data structure,
based on the peer connectivity reports, that identifies Li-Fi APs that can receive
communication handover from other identified Li-Fi APs. The coordination node is further
configured to determine an identifier of a first Li-Fi AP providing Li-Fi communication
service for a UE, and access the handover pathway data structure using the identifier
of the first Li-Fi AP to determine an identifier of a second Li-Fi AP to which handover
from the first Li-Fi AP can be performed. The coordination node then initiates handover
of the Li-Fi communication service for the UE from the first Li-Fi AP to the second
Li-Fi AP.
[0007] A potential advantage of this approach is that it can provide more efficient and
robust management of handover of UE communications between Li-Fi APs. The coordination
node can use the peer connectivity reports from the Li-Fi APs to dynamically update
a handover pathway data structure to track changes in the handover opportunities between
particular ones of the Li-Fi APs, such as when doors become open or closed, when Li-Fi
APs become powered on or power off, and/or when other events occur that change the
communication capability of one or more of the Li-Fi APs. In view of the relatively
small coverage areas provided by individual ones of the Li-Fi APs, developing and
using a handover pathway data structure as disclosed herein can enable handover decisions
to be quickly made based on the current availability of Li-Fi APs for handover from
particular other Li-Fi APs.
[0008] Other embodiments are directed to a system comprising the coordination node and a
Li-Fi AP for communicating with UEs under control of a coordination node areas. The
Li-Fi AP of the system is configured to receive Li-Fi signals from observed Li-Fi
APs, where the Li-Fi signals provide identifiers of the observed Li-Fi APs, to generate
a peer connectivity report containing an identifier of the Li-Fi AP and the identifiers
of the observed Li-Fi APs, and to report the peer connectivity report to the coordination
node.
[0009] Some other related embodiments are directed to a method performed by a system comprising
a coordination node for controlling communications between Li-Fi APs and UEs, and
a Li-Fi AP for communicating with UEs under control of the coordination node. The
method comprises receiving, by the Li-Fi AP, Li-Fi signals from observed Li-Fi APs,
where the Li-Fi signals provide identifiers of the observed Li-Fi APs. The method
further comprises generating, by the Li-Fi AP, a peer connectivity report containing
an identifier of the Li-Fi AP and the identifiers of the observed Li-Fi APs, and reporting,
by the Li-Fi AP, the peer connectivity report to the coordination node. The method
further comprises receiving, by the coordination node, peer connectivity reports from
Li-Fi APs which identify Li-Fi APs having at least partially overlapping coverage
areas, and developing, by the coordination node, a handover pathway data structure,
based on the peer connectivity reports, that identifies Li-Fi APs that can receive
communication handover from other identified Li-Fi APs. The method further comprises
determining, by the coordination node, an identifier of a first Li-Fi AP providing
Li-Fi communication service for a UE, and accessing the handover pathway data structure
using the identifier of the first Li-Fi AP to determine an identifier of a second
Li-Fi AP to which handover from the first Li-Fi AP can be performed. The method then
initiates, by the coordination node, handover of the Li-Fi communication service for
the UE from the first Li-Fi AP to the second Li-Fi AP.
[0010] Other methods, coordination nodes, Li-Fi APs, and computer program products according
to embodiments will be or become apparent to one with skill in the art upon review
of the following drawings and detailed description. It is intended that all such additional
methods, coordination nodes, Li-Fi APs, and computer program products be included
within this description and protected by the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Aspects of the present disclosure are illustrated by way of example and are not limited
by the accompanying drawings. In the drawings:
Figure 1 is a block diagram of a system that includes a coordination node that controls
handover of UE communications between Li-Fi APs in accordance with some embodiments
of the present disclosure;
Figure 2 illustrates Li-Fi APs to provide Li-Fi communication service within a building,
and for which a handover pathway data structure is developed by the coordination node
of Figure 1, in accordance with some embodiments of the present disclosure;
Figure 3a illustrates 7 Li-Fi APs spaced apart within 3 rooms which have an open pathway
there between through which a user can transport a UE;
Figure 3b graphically illustrates a handover pathway data structure developed by the
coordination node of Figure 1 for use in controlling handoff of UEs between the 7
Li-Fi APs of Figure 3a, in accordance with some embodiments of the present disclosure;
Figure 4a illustrates the 7 Li-Fi APs of Figure 3a but differs therefrom based on
a door being closed between 2 of the adjacent rooms;
Figure 4b graphically illustrates how the handover pathway data structure is modified
to correspond to discovery of an absence of handover connectivity between the now
closed-off 2 adjacent rooms, in accordance with some embodiments of the present disclosure;
Figure 5 is a combined data flow diagram and flowchart of operations by two Li-Fi
APs to provide peer connectivity reports to the coordination node 110 for development
of a handover pathway data structure in accordance with some embodiments of the present
disclosure;
Figure 6 is a combined data flow diagram and flowchart of further operations by the
coordination node, the two Li-Fi APs, and the UE of Figure 5 to perform handover of
the UE using the handover pathway data structure in accordance with some embodiments
of the present disclosure;
Figure 7 is a flowchart of operations and methods by a coordination node to control
the initiation of handover between Li-Fi APs and UEs in accordance with some embodiments
of the present disclosure;
Figures 8-11 are flowcharts of operations and methods by a Li-Fi AP to generate peer
connectivity reports that are sent to a coordination node in accordance with some
embodiments of the present disclosure;
Figure 12 is a block diagram of a coordination node that is configured according to
some embodiments of the present disclosure;
Figure 13 is a block diagram of modules forming a coordination node that are configured
according to some embodiments of the present disclosure;
Figure 14 is a block diagram of a Li-Fi AP that is configured according to some embodiments
of the present disclosure; and
Figure 15 is a block diagram of modules forming a Li-Fi AP that are configured according
to some embodiments of the present disclosure.
DETAILED DESCRIPTION
[0012] Inventive concepts will now be described more fully hereinafter with reference to
the accompanying drawings, in which examples of embodiments of inventive concepts
are shown. Inventive concepts may, however, be embodied in many different forms and
should not be construed as limited to the embodiments set forth herein. Rather, these
embodiments are provided so that this disclosure will be thorough and complete, and
will fully convey the scope of various present inventive concepts to those skilled
in the art. It should also be noted that these embodiments are not mutually exclusive.
Components from one embodiment may be tacitly assumed to be present/used in another
embodiment.
[0013] Li-Fi APs are anticipated to be used predominately indoors where communication coverage
areas can overlap in complex ways and where mobility of UEs, such as while a user
is walking down a hallway, can complicate the ability of such systems to maintain
reliable communication links to such UEs. Embodiments of the present disclosure are
directed to improving UE mobility between Li-Fi APs in environments where some of
the coverage areas can dynamically change due to, for example, doors opening/closing
and individual Li-Fi APs being switched on/off.
[0014] Figure 1 is a block diagram of a system that includes a coordination node 110 that
controls handover of UE communications between Li-Fi APs 130 in accordance with some
embodiments of the present disclosure. The Li-Fi APs 130 are connected to a wide area
network (WAN) 150 through a local area network (LAN) switch 140 via, e.g., a power
line network through a common power line, through Wi-Fi wireless RF connection, or
other wired/wireless connection. The Li-Fi APs 130 emit Li-Fi signals and receive
Li-Fi signals emitted by UEs 108, to provide communication services in their respective
coverage areas. The Li-Fi signals may be within the visible light portion of the electromagnetic
spectrum and encoded to communicate data between the UEs 108 and Li-Fi APs 130 for
routing through, e.g., the local area network (LAN) switch 140 and the wide area network
(WAN) 150. In the illustrated example, spatially adjacent Li-Fi APs 130 have partially
overlapping or nearly overlapping coverage areas. The coordination node 110 operates
to control handover of UE communications between individual ones of the Li-Fi APs
130 to maintain continuous or nearly continuous communication capability as a person
carries the UE 108 from the coverage area of one Li-Fi AP 130 into the coverage area
of another Li-Fi AP 130.
[0015] In accordance with various embodiments, handover between Li-Fi APs 130 can be improved
by the coordination node 110 developing a handover pathway data structure which is
used for handover of UE communications between the Li-Fi APs 130. The handover pathway
data structure can be updated over time to dynamically track changes that occur in
the availability of Li-Fi APs 130 for use in UE handover.
[0016] The coordination node 110 uses peer connectivity reports received from the Li-Fi
APs 130 to develop the handover pathway data structure. Li-Fi APs 130 can generate
the peer connectivity reports based on identifying from which, if any, other Li-Fi
APs 130 it receives Li-Fi signals. The peer connectivity reports can be generated
to contain information identifying the other Li-Fi APs 130. The handover pathway data
structure can be retained in memory of a repository 120. Li-Fi APs 130 may periodically
share their peer connectivity reports with other observable Li-Fi APs 130 through
Li-Fi signaling or other communication signaling therebetween. A Li-Fi AP 130 can
use a peer connectivity report from another Li-Fi AP 130 to update its local peer
connectivity information, and which it can use to generate the peer connectivity reports.
[0017] As will be explained in further detail below, handover between Li-Fi APs 130 can
be initiated by the coordination node 110 in response a determination that a communication
signal quality measurement, e.g., signal strength and/or bit error rate, has dropped
below a defined quality threshold. Comparison of the communication signal quality
measurement to the defined quality threshold may be performed by the UE 108 based
on a Li-Fi signal received from a Li-Fi AP 130, by the Li-Fi AP 130 based on a Li-Fi
signal received from the UE 108, and/or by the coordination node 110 based on receipt
of the communication signal quality measurement from the Li-Fi AP 130.
[0018] Figure 2 illustrates Li-Fi APs 130 that are spaced apart to provide Li-Fi communication
coverage areas in various rooms and hallways within a building. Referring to Figure
2 it is observed that some of the Li-Fi APs 130 have partially overlapping coverage
areas because they can emit and receive Li-Fi signals passing through various door
and other openings between the rooms, hallways, stairwells, etc. between adjacent
coverage areas. The connection node 110 of Figure 1 is configured to initiate handover
between the Li-Fi APs 130 of ongoing Li-Fi communications with a UE as a person transports
the UE throughout the building. The connection node 110 develops a handover pathway
data structure for the building, which it uses to carry out initiation of handover.
[0019] Figure 3a illustrates 7 Li-Fi APs (named A-E, G, H) spaced apart within 3 rooms (Rooms
101, 102, 103) which have an open pathway between the adjacent rooms, and through
which a user can transport a UE. Figure 3b graphically illustrates an example handover
pathway data structure developed by the coordination node 110 of Figure 1 for use
in controlling handoff of UEs between the 7 Li-Fi APs of Figure 3a. The example handover
pathway data structure contains information identifying that Li-Fi AP (A) can handoff
to Li-Fi APs (B), (C), and (D); Li-Fi AP (D) can handoff to Li-Fi APs (A) and (E);
and Li-Fi AP (E) can handoff to Li-Fi APs (G) and (H). Thus, for example, when a handover
condition becomes satisfied for an ongoing Li-Fi communication service for a UE, e.g.,
such as when a UE signal quality measurement drops below a quality threshold, the
coordination node 110 accesses the handover pathway data structure using the identifier
of the current Li-Fi AP to determine an identifier of one or more other Li-Fi APs
to which the Li-Fi communication service for the UE can be handed over. The coordination
node then initiates handover of the Li-Fi communication service for the UE from the
current Li-Fi AP to the identified one or more other Li-Fi APs or to a further selected
one of a plurality of the available Li-Fi APs. The quality threshold may correspond
to any one or more of: a signal strength threshold, a bit error rate threshold, etc.
[0020] Further example operations are now explained in view of the coverage scenario of
Figure 3b. As a UE is transported from the coverage area of Li-Fi AP (A) into the
coverage area of Li-Fi AP (B), the signal strength measurements by the UE of Li-Fi
signals from the Li-Fi AP (A) will fall below a signal strength threshold. The UE
can report the signal strength measurements through one or both of the Li-Fi APs (A)
and (B) to the coordination node 110. The coordination node 110 accesses the handover
pathway data structure to determine that handover from Li-Fi AP (A) to Li-Fi AP (B),
Li-Fi AP (C), and Li-Fi AP (D) is allowed. In one embodiment, the coordination node
110 can initiate handover of the ongoing Li-Fi communication service for the UE from
Li-Fi AP (A) to the group of Li-Fi APs (B), (C), and (D). In a further embodiment,
the coordination node 110 selects Li-Fi AP (B) as a best candidate among the group
of available Li-Fi APs, and responsively initiates handover of the ongoing Li-Fi communication
service for the UE from Li-Fi AP (A) to Li-Fi AP (B).
[0021] Further related operations are explained in the context of as the UE is transported
from the coverage area of Li-Fi AP (A) into the coverage area of Li-Fi AP (D), the
UE can report signal strength measurements indicating that Li-Fi signals received
from Li-Fi AP (A) have fallen below the signal strength threshold while signal strength
measurements of Li-Fi signals received from Li-Fi AP (D) have risen above the signal
strength threshold. The reported measurements can trigger the coordination node 110
to determine from the handover pathway data structure that handover from Li-Fi AP
(A) to Li-Fi AP (D) is allowed and, responsively, initiate handover of the ongoing
Li-Fi communication service for the UE from Li-Fi AP (A) to Li-Fi AP (D).
[0022] Figure 4a illustrates the 7 Li-Fi APs of Figure 3a but differs therefrom based on
a door being closed between adjacent rooms 101 and 102, thereby preventing Li-Fi AP
(A) from receiving Li-Fi signals from Li-Fi AP (D) and vice versa. Other events that
can cause Li-Fi APs to no longer receive Li-Fi signal from one another, can include
becoming powered-off, becoming inoperative to emit Li-Fi signals, becoming inoperative
to receive Li-Fi signals, etc. Figure 4b graphically illustrates how the example handover
pathway data structure has been developmentally modified by the coordination node
110 responsive to discovering, through one or more peer connectivity reports received
from Li-Fi AP (A) and/or Li-Fi AP (D), that Li-Fi AP (A) can no longer detect Li-Fi
signals from Li-Fi AP (D) or vice versa. Information contained in the example handover
pathway data structure of Figure 3b is therefore modified by the coordination node
110 so that Li-Fi AP (A) is no longer indicated in Figure 4b as having the ability
to handoff to Li-Fi AP (D) and vice versa.
[0023] Further example operations are explained in view of the coverage scenario of Figure
4b, as a UE is transported from the coverage area of Li-Fi AP (A) into the coverage
area of Li-Fi AP (B), the signal strength measurements by the UE of Li-Fi signals
from the Li-Fi AP (A) will fall below a signal strength threshold. The UE can report
the signal strength measurements through one or both of the Li-Fi APs (A) and (B)
to the coordination node 110. The coordination node 110 accesses the handover pathway
data structure and determines that handover from Li-Fi AP (A) to Li-Fi AP (B) and
Li-Fi AP (C) is allowed. In one embodiment, the coordination node 110 can initiate
handover of the ongoing Li-Fi communication service for the UE from Li-Fi AP (A) to
the group of Li-Fi APs (B) and (C). In contrast to the example of Figure 3b, the coordination
node 110 does not initiate handover of the ongoing Li-Fi communication service to
the Li-Fi AP (D) because that AP is not indicated to be presently available for handover
from Li-Fi AP (A).
[0024] In this manner, when a peer connectivity report from a Li-Fi AP 130 indicates that
it has received signals from another Li-Fi AP 130, the coordination node 110 determines
that the two Li-Fi APs 130 have at least partially overlapping coverage areas and
responsively updates the corresponding handover information for those Li-Fi APs 130
in the handover pathway data structure. The coordination node 110 can similarly update
the corresponding handover information for those Li-Fi APs 130 in the handover pathway
data structure to indicate when those Li-Fi APs 130 are no longer indicated by the
peer connectivity reports to be able to receive signals from each other. The coordination
node 110 thereby learns over time and updates the handover pathway data structure
to indicate which Li-Fi APs 130 have at least partially overlapping communication
coverage areas and can be used for performing handover of Li-Fi communication service
for UEs.
[0025] Figure 5 is a combined data flow diagram and flowchart of operations by two Li-Fi
APs (first and second Li-Fi APs) to provide peer connectivity reports to the coordination
node 110 for development of a handover pathway data structure in accordance with some
embodiments of the present disclosure. Figure 6 is a combined data flow diagram and
flowchart of further operations by the coordination node 110, the first and second
Li-Fi APs, and the UE 108 of Figure 5 to perform handover of the UE 108 using the
handover pathway data structure in accordance with some embodiments of the present
disclosure. Figure 7 is a flowchart of operations and methods by the coordination
node 110 to control the initiation of handover between Li-Fi APs 130 and UEs 108 in
accordance with some embodiments of the present disclosure. Figures 8-11 are flowcharts
of operations and methods by the Li-Fi APs 130 to generate peer connectivity reports
that are sent to the coordination node 110 in accordance with some embodiments of
the present disclosure.
[0026] Various operations that can be performed by the Li-Fi APs 130 to generate peer connectivity
reports for communication to the coordination node 110, and by the coordination node
110 to develop a handover pathway data structure therefrom are now explained in the
context of Figures 5 and 8. The second Li-Fi AP 130 receives (block 500 of Fig. 5,
block 800 of Fig. 8) a Li-Fi signal from the first Li-Fi AP 130. The Li-Fi signal
provides an identifier of the first Li-Fi AP 130. The second Li-Fi AP 130 generates
(block 802) a peer connectivity report containing an identifier of the Li-Fi AP 130
and the identifier of the first Li-Fi APs 130. When the second Li-Fi AP 130 receives
Li-Fi signals from other observable Li-Fi APs 130, it generates the peer connectivity
report to further contain identifiers of each of the observable Li-Fi APs 130. The
second Li-Fi APs 130 reports (blocks 502 and 804) the peer connectivity report to
the coordination node 110. The operations of second Li-Fi AP 130 within dashed box
510 can be similarly performed by the first Li-Fi AP 130 responsive to Li-Fi signals
received from the second Li-Fi AP 130 and any other observable Li-Fi APs 130, to communicate
a peer connectivity report to the coordination node 110.
[0027] The coordination node 110 uses the received peer connectivity reports to develop
(block 504) a handover pathway data structure. Example operations that may be performed
by the coordination node 110 to develop the handover data structure are shown in Figure
7. With further reference to Figure 7, the coordination node 110 receives (blocks
502 and 700) peer connectivity reports from Li-Fi APs 130 which identify Li-Fi APs
having at least partially overlapping coverage areas, i.e., based on the Li-Fi APs
receiving signals from other Li-Fi APs. The coordination node 110 develops (blocks
504 and 702) the handover pathway data structure, based on the peer connectivity reports,
that identifies Li-Fi APs 130 that can receive communication handover from other identified
Li-Fi APs 130. The coordination node 110 may store the handover pathway data structure
in memory of the repository 120.
[0028] In one embodiment, operations to develop (blocks 504 and 702) the handover pathway
data structure, include determining an identifier of a reporting Li-Fi AP 130 (i.e.,
the first Li-Fi AP) that reported one of the peer connectivity reports to the coordination
node 110, determining an identifier of one or more observed Li-Fi APs 130 (i.e., the
second Li-Fi AP) based on content of the one of the peer connectivity reports, and
storing in the handover pathway data structure the identifier of the one or more observed
Li-Fi APs 130 (i.e., the second Li-Fi AP) with a logical association to the identifier
of the reporting Li-Fi AP 130 (i.e., the first Li-Fi AP). Operations to determine
(blocks 604 and 704) an identifier of a first Li-Fi AP 130 providing Li-Fi communication
service for the UE 108, can include receiving (e.g., signaling 600 in Fig. 6) a report
containing a measurement by the UE 108 of a Li-Fi signal transmitted by the first
Li-Fi AP 130, and responsive to determining that the measurement does not satisfy
a signal quality threshold, performing the initiating handover (blocks 608 and 708)
of the Li-Fi communication service for the UE 108 from the first Li-Fi AP 130 to the
second Li-Fi AP 130.
[0029] The coordination node 110 may receive Li-Fi signal measurements reported by the Li-Fi
APs 130, and use the signal measurements to determine whether to update the handover
pathway data structure based on the Li-Fi APs 130 identified in the reports. For example,
when a peer connectivity report from the first Li-Fi AP 130 contains a measurement
of a signal received from the second Li-Fi AP 130 that is determined to be less than
a signal quality threshold, the coordination node 110 may choose not to add the second
Li-Fi AP 130 to the handover pathway data structure since it should not be an allowable
candidate for handover from the first Li-Fi AP 130. Moreover, when the handover pathway
data structure presently lists the second Li-Fi AP 130 as an allowable candidate for
handover from the first Li-Fi AP 130 and the received signal measurement is less than
the signal quality threshold, the coordination node 110 may remove the second Li-Fi
AP 130 from the listing associated with the first Li-Fi AP 130 since it should no
longer be an allowable candidate for handover from the first Li-Fi AP 130.
[0030] Related illustrative operations can include generating the peer connectivity reports
to contain pairs of an identifier of one of the one or more observed Li-Fi APs 130
and a measurement by the reporting Li-Fi AP 130 of a Li-Fi signal received from the
one of the one or more observed Li-Fi APs 130. Referring to the operations shown in
Figure 11, a Li-Fi AP 130 measures (block 1100) the Li-Fi signals received from observed
Li-Fi APs 130, and generates (block 1102) a peer connectivity report to contain the
measurements with defined associations to the identifiers of the observed Li-Fi APs
130.
[0031] The coordination node 110 can selectively perform storing in the handover pathway
data structure of the identifier of the observed Li-Fi AP 130 with a logical association
to the identifier of the reporting Li-Fi AP 130, only if the measurement by the reporting
Li-Fi AP 130 of the Li-Fi signal received from the one of the one or more observed
Li-Fi APs 130 satisfies a signal quality threshold.
[0032] The handover pathway data structure may be selectively updated only if the received
signal measurement indicates that a signal strength threshold is satisfied and/or
that a bit error rate threshold is satisfied. In one further embodiment, the identifier
of the one of the one or more observed Li-Fi APs 130 is selectively stored in the
handover pathway data structure with a logical association to the identifier of the
reporting Li-Fi AP 130, only if a signal strength indicated by the measurement satisfies
a signal strength threshold. In an alternative or additional further embodiment, the
identifier of the one of the one or more observed Li-Fi APs 130 is selectively stored
in the handover pathway data structure with a logical association to the identifier
of the reporting Li-Fi AP 130, only if a bit error rate indicated by the measurement
satisfies a bit error rate threshold.
[0033] The signal measurements reported by a Li-Fi AP 130 can be used to select a particular
Li-Fi AP 130 from among a group of candidate Li-Fi APs 130 for use in initiating handover.
At least some of the peer connectivity reports received by the coronation node 110
can contain pairs of an identifier of an observed Li-Fi APs 130 and a measurement
by the reporting Li-Fi AP 130 of a Li-Fi signal received from the observed Li-Fi APs
130. The coordination node 110 can store the pairs in the handover pathway data structure
with a logical association to the identifier of the reporting Li-Fi AP 130. The coordination
node's 110 access (blocks 606 and 706) of the handover pathway data structure using
the identifier of the first Li-Fi AP 130 can therefore identify a plurality of candidate
Li-Fi APs 130. The coordination node 110 can select the second Li-Fi AP 130 from among
the candidate Li-Fi APs 130 based on comparison of the measurements associated with
the candidate Li-Fi APs 130 which are retrieved from the handover pathway data structure.
[0034] The coordination node 110 can further update the handover pathway data structure
to remove a particular Li-Fi AP 130 from being associated with a reporting Li-Fi AP
130 when it becomes absent for threshold elapsed time from peer connectivity reports
received from the reporting Li-Fi AP 130. Accordingly, the operations performed by
the coordination node 110 to develop (blocks 504 and 702) the handover pathway data
structure can include the following operations. Subsequent to storing an identifier
of an observed Li-Fi AP with a logical association to an identifier of a reporting
Li-Fi AP in the handover pathway data structure, the coordination node 110 can determine
that an absentee one of the observed Li-Fi APs 130 has not been identified in a peer
connectivity report received from the reporting Li-Fi AP 130 in at least a threshold
elapsed time. The coordination node can responsively remove from the handover pathway
data structure the identifier of the absentee one of the observed Li-Fi APs 130 and
its logical association to the identifier of the reporting Li-Fi AP 130.
[0035] Corresponding operations by a Li-Fi AP 130 and include subsequent to a reporting
of the peer connectivity report to the coordination node 110, determining that a Li-Fi
signal has not been received from one of the observed Li-Fi APs 130 contained in the
peer connectivity report in at least a threshold elapsed time, and excluding the one
of the observed Li-Fi APs 130 from another peer connectivity report that is next reported
to the coordination node 110 responsive to the determination. Thus, the Li-Fi AP 130
can selectively include identifiers for various previously observed Li-Fi APs 130
depending upon whether the Li-Fi AP 130 has received a Li-Fi signal therefrom within
the threshold elapsed time.
[0036] Responsive to a determination that handover of Li-Fi communication service for the
UE 108 is needed or responsive to another defined event, the coordination node 110
determines (block 704) an identifier of the first Li-Fi AP 130 providing Li-Fi communication
service for the UE 108, and accesses (block 706) the handover pathway data structure
using the identifier of the first Li-Fi AP 130 to determine an identifier of a second
Li-Fi AP 130 to which handover from the first Li-Fi AP 130 can be performed. The coordination
node 110 then initiates handover (block 708) of the Li-Fi communication service for
the UE 108 from the first Li-Fi AP 130 to the second Li-Fi AP 130.
[0037] A potential advantage of this approach is that it can provide more efficient and
robust management of handover of UE communications between Li-Fi APs 130. The coordination
node 110 can use the peer connectivity reports from the Li-Fi APs 130 to dynamically
update a handover pathway data structure to track changes in the handover opportunities
between particular ones of the Li-Fi APs 130, such as when doors become open or closed,
when Li-Fi APs 130 become powered on or power off, and/or when other events occur
that change the communication capability of one or more of the Li-Fi APs 130. In view
of the relatively small coverage areas provided by individual ones of the Li-Fi APs,
developing and using a handover pathway data structure as disclosed herein can enable
handover decisions to be quickly made based on the current availability of Li-Fi APs
for handover from particular other Li-Fi APs.
[0038] Further operations that can be performed by the Li-Fi APs 130 and the coordination
node 110 to trigger and perform handover, are now described in the context of Figures
6 and 9-11.
[0039] In the operational scenario of Figure 5, the first Li-Fi AP 130 is providing Li-Fi
communication service to the UE 108. The first Li-Fi AP 130 may perform signal measurements
on Li-Fi signals received from the UE 108 and/or may receive signal measurements performed
by the UE 108 on Li-Fi signals received from the first Li-Fi AP 130 and/or other identified
Li-Fi APs, such as the second Li-Fi AP 130.
[0040] In some embodiments, handover decisions are performed by the coordination node 110
using signal measurements reported by the various Li-Fi APs 130. In the example operations
of Figure 6, the first Li-Fi AP 130 can report (block 602) signal measurements to
the coordination node 110. The signal measurements may be performed by the first Li-Fi
AP 130 and/or by the UE 108. According to the operational embodiment of Figure 9,
the first Li-Fi AP 130 measures (block 900) a Li-Fi signal received from the UE (108)
during Li-Fi communication service by the first Li-Fi AP 130 for the UE (108), and
includes (block 902) an indication of the measurement in the peer connectivity report
reported to the coordination node 110. Alternatively or additionally, the first Li-Fi
AP 130 receives (block 602) from the UE 108 measurements by the UE 108 of Li-Fi signals
transmitted by the first Li-Fi AP 130 and/or received from other Li-Fi APs 130, such
as from the second Li-Fi AP 130. The first Li-Fi AP 130 responsively reports (blocks
502, 602, 804) an indication of the measurements in the peer connectivity report.
The measurements may alternatively or additionally be communicated in reporting messages
that are separate from the peer connectivity reports.
[0041] In some other embodiments, handover decisions are performed by the Li-Fi APs 130
using signal measurements received from UEs 108 and/or using signal measurements they
perform on Li-Fi signals received from UEs 108. In the embodiment of Figure 6, the
first Li-Fi AP 130 compares signal measurements, received from a UE 108 and/or performed
on Li-Fi signals received from the UE 108, to a signal quality threshold. Responsive
to the signal measurement not satisfying the signal quality threshold, the first Li-Fi
AP 130 sends a handover request message to the coordination node 110, where the handover
request message contains an identifier of the first Li-Fi AP may further contain an
identifier of the UE 108.
[0042] The coordination node 110 determines (blocks 604 of Fig. 6 and 704 of Fig. 7) an
identifier of the first Li-Fi AP 130 providing Li-Fi communication service for the
UE 108. The coordination node 110 may determine (blocks 604 and 704) the identifier
of the first Li-Fi AP 130 by operations that include parsing the handover request
message received from the first Li-Fi AP 130 to determine the identifier of the first
Li-Fi AP 130.
[0043] The coordination node 110 accesses (blocks 606 and 706) the handover pathway data
structure using the identifier of the first Li-Fi AP 130 to determine an identifier
of a second Li-Fi AP 130 to which handover from the first Li-Fi AP 130 can be performed,
and initiates handover (blocks 608 and 708) of the Li-Fi communication service for
the UE 108 from the first Li-Fi AP 130 to the second Li-Fi AP 130 that is identified.
The second Li-Fi AP 130 subsequently operates to provide (block 610) Li-Fi communication
service for the UE 108, and which may or may not be performed without interruption
of a flow of data packets to the UE 108.
[0044] Operations by the coordination node 110 to initiate handover (blocks 608 and 708)
can include initiating re-routing of data packets that are addressed to the UE 108,
to be directed to the second Li-Fi AP 130 instead of to the first Li-Fi AP 130. Such
data packet rerouting may be initiated by the coordination node 110 sending instructions
to the LAN switch 140. Alternative or additional operations by the coordination node
110 to initiate handover can include sending a handover message to the first Li-Fi
AP 130 that contains both the address of the UE 108 and the identifier of the second
Li-Fi AP 130 to which the handover is being performed.
[0045] Operations by the first Li-Fi AP 130 for performing handover according to one embodiment
is shown in Figure 10. The first Li-Fi AP 130 receives (block 1000) the handover message,
and responsively performs (block 1002) handover of the Li-Fi communication service
for the identified UE 108 from the first Li-Fi AP 130 to the second Li-Fi AP 130 that
is identified in the handover message. In still another embodiment, the first Li-Fi
AP 130 can receive the handover message, and responsively forward the handover message
to the UE 108 to trigger the UE 108 to initiate handover of the Li-Fi communication
service from the first Li-Fi AP 130 to the second Li-Fi AP 130.
[0046] Although various embodiments have been explained in which the coordination node 110
directly controls operation of the first and second Li-Fi APs 130, in some other embodiments
the coordination node 110 operates to coordinate negotiations between the Li-Fi APs
130. The coordination node 110 may operate to coordinate negotiations between the
first and second Li-Fi APs 130 to perform the handover of the Li-Fi communication
service for the UE 108. Accordingly, decentralized handover decision-making can be
performed by the various Li-Fi APs 130 instead of via centralized handover decision-making
by the coordination node 110. The ordination node 110 may communicate handover related
information, obtained from its accessing (blocks 606 and 706) of the handover pathway
data structure, to the first Li-Fi AP 130 and/or the second Li-Fi AP 130 to enable
their negotiation of handover of Li-Fi communication service for the UE 108. The negotiations
may be performed using negotiation messaging that is communicated through the intervening
coordination node 110 and/or that is communicated directly between the Li-Fi APs 130.
[0047] In a situation when the coordination node 110 does not identify a particular Li-Fi
AP 130 from the handover pathway data structure that can be used for handover, the
coordination node 110 may responsively initiate handover to a group of Li-Fi APs 130.
In one embodiment, responsive to the accessing (blocks 606 and 706) of the handover
pathway data structure resulting in return of no identifier of another Li-Fi AP 130
as having been defined as associated with the identifier of the first Li-Fi AP 130,
the coordination node 110 initiates handover (blocks 608 and 708) of the Li-Fi communication
service for the UE 108 from the first Li-Fi AP 130 to a group of Li-Fi APs 130 at
least one of which that is likely to have a coverage area that includes the UE 108.
For example, the coordination node 110 may be configured to initiate re-routing of
data packets for the UE 108 to all Li-Fi APs within a defined graphic area of the
first Li-Fi AP 130, such as all Li-Fi APs have been defined to be proximately located
to the first Li-Fi AP 130. For example, as explained above regarding Figure 3b, when
a UE being serviced by Li-Fi AP (A) is carried away from that service area, the coordination
node 110 may responsively initiate handover of communication service for the UE to
a group of Li-Fi APs (B), (C), and (D).
[0048] Figure 12 is a block diagram of the coordination node 110 that is configured according
to some embodiments of the present disclosure. The coordination node 110 includes
a processor 1200, a memory 1210, and a network interface circuit which may include
Li-Fi network transceiver circuit 1226, and/or may include a radio and/or wired network
interface 1224 (e.g., Ethernet interface). The radio network interface 1224 can include,
but is not limited to, a LTE or other cellular transceiver, WiFi transceiver (IEEE
802.11), Bluetooth, WiMax transceiver, or other wireless communication transceiver
configured to communicate with the Li-Fi APs 130.
[0049] The processor 1200 may include one or more data processing circuits, such as a general
purpose and/or special purpose processor (e.g., microprocessor and/or digital signal
processor) that may be collocated or distributed across one or more networks. The
processor 1200 is configured to execute computer program code 1212 in the memory 1210,
described below as a non-transitory computer readable medium, to perform at least
some of the operations described herein as being performed by a coordination node.
The memory 1210 may further include the Li-Fi AP handover pathway data structure repository
120. The coordination node 110 may further include a user input interface 1220 (e.g.,
touch screen, keyboard, keypad, etc.) and a display device 1222.
[0050] Figure 13 is a block diagram of modules 1300 forming a coordination node that is
configured according to some embodiments of the present disclosure. Referring to Figure
13, the modules 1300 include a receiving module 1300, a handover pathway development
module 1302, a determining module 1304, a handover pathway access module 1306, and
a handover module 1308. The receiving module 1300 is for receiving (block 502 and
700) peer connectivity reports from Li-Fi APs 130 which identify Li-Fi APs having
at least partially overlapping coverage areas. The handover pathway development module
1302 is for developing (blocks 504 and 702) a handover pathway data structure, based
on the peer connectivity reports, that identifies Li-Fi APs 130 that can receive communication
handover from other identified Li-Fi APs 130. The determining module 1304 is for determining
(blocks 604 and 704) an identifier of a first Li-Fi AP 130 providing Li-Fi communication
service for a UE 108. The handover pathway access module 1306 is for accessing (blocks
606 and 706) the handover pathway data structure using the identifier of the first
Li-Fi AP 130 to determine an identifier of a second Li-Fi AP 130. The handover module
1308 is for initiating handover (blocks 608 and 708) of the Li-Fi communication service
for the UE 108 from the first Li-Fi AP 130 to the second Li-Fi AP 130.
[0051] Figure 14 is a block diagram of a Li-Fi AP 130 that is configured according to some
embodiments of the present disclosure. The Li-Fi AP 130 includes a processor 1400,
a memory 1410, a Li-Fi transceiver circuit 1420, and may further include a wired network
interface 1422 (e.g., Ethernet) and/or a radio network transceiver circuit 1424. The
Li-Fi transceiver circuit 1420 is configured to communicate with UEs 108 according
to or more embodiments herein. The radio network transceiver circuit 1424 can include,
but is not limited to, a LTE or other cellular transceiver, WIFI transceiver (IEEE
802.11), Bluetooth, WiMax transceiver, or other wireless communication transceiver
configured to communicate with the coordination node 110.
[0052] The processor 1400 may include one or more data processing circuits, such as a general
purpose and/or special purpose processor (e.g., microprocessor and/or digital signal
processor) that may be collocated or distributed across one or more networks. The
processor 1400 is configured to execute computer program code 1412 in the memory 1410,
described below as a non-transitory computer readable medium, to perform at least
some of the operations described herein as being performed by a Li-Fi AP.
[0053] Figure 15 is a block diagram of modules 1300 forming a Li-Fi AP that is configured
according to some embodiments of the present disclosure. Referring to Figure 15, the
modules 1500 include a receiving module 1500, a report generating module 1502, and
a communication module 1504. The receiving module is for receiving (blocks 500 and
800) Li-Fi signals from observed Li-Fi APs 130, where the Li-Fi signals provide identifiers
of the observed Li-Fi APs 130. The report generating module 1502 is for generating
(block 802) a peer connectivity report containing an identifier of the Li-Fi AP 130
and the identifiers of the observed Li-Fi APs 130. The communication module 1504 is
for reporting (blocks 502 and 804) the peer connectivity report to the coordination
node (110).
Further Definitions and Embodiments:
[0054] In the above-description of various embodiments of present inventive concepts, it
is to be understood that the terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of present inventive
concepts. Unless otherwise defined, all terms (including technical and scientific
terms) used herein have the same meaning as commonly understood by one of ordinary
skill in the art to which present inventive concepts belongs. It will be further understood
that terms, such as those defined in commonly used dictionaries, should be interpreted
as having a meaning that is consistent with their meaning in the context of this specification
and the relevant art and will not be interpreted in an idealized or overly formal
sense expressly so defined herein.
[0055] When an element is referred to as being "connected", "coupled", "responsive", or
variants thereof to another element, it can be directly connected, coupled, or responsive
to the other element or intervening elements may be present. In contrast, when an
element is referred to as being "directly connected", "directly coupled", "directly
responsive", or variants thereof to another element, there are no intervening elements
present. Like numbers refer to like elements throughout. Furthermore, "coupled", "connected",
"responsive", or variants thereof as used herein may include wirelessly coupled, connected,
or responsive. As used herein, the singular forms "a", "an" and "the" are intended
to include the plural forms as well, unless the context clearly indicates otherwise.
Well-known functions or constructions may not be described in detail for brevity and/or
clarity. The term "and/or" includes any and all combinations of one or more of the
associated listed items.
[0056] It will be understood that although the terms first, second, third, etc. may be used
herein to describe various elements/operations, these elements/operations should not
be limited by these terms. These terms are only used to distinguish one element/operation
from another element/operation. Thus a first element/operation in some embodiments
could be termed a second element/operation in other embodiments without departing
from the teachings of present inventive concepts. The same reference numerals or the
same reference designators denote the same or similar elements throughout the specification.
[0057] As used herein, the terms "comprise", "comprising", "comprises", "include", "including",
"includes", "have", "has", "having", or variants thereof are open-ended, and include
one or more stated features, integers, elements, steps, components or functions but
does not preclude the presence or addition of one or more other features, integers,
elements, steps, components, functions or groups thereof. Furthermore, as used herein,
the common abbreviation "e.g.", which derives from the Latin phrase "exempli gratia,"
may be used to introduce or specify a general example or examples of a previously
mentioned item, and is not intended to be limiting of such item. The common abbreviation
"i.e.", which derives from the Latin phrase "id est," may be used to specify a particular
item from a more general recitation.
[0058] Example embodiments are described herein with reference to block diagrams and/or
flowchart illustrations of computer-implemented methods, apparatus (systems and/or
devices) and/or computer program products. It is understood that a block of the block
diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams
and/or flowchart illustrations, can be implemented by computer program instructions
that are performed by one or more computer circuits. These computer program instructions
may be provided to a processor circuit of a general purpose computer circuit, special
purpose computer circuit, and/or other programmable data processing circuit to produce
a machine, such that the instructions, which execute via the processor of the computer
and/or other programmable data processing apparatus, transform and control transistors,
values stored in memory locations, and other hardware components within such circuitry
to implement the functions/acts specified in the block diagrams and/or flowchart block
or blocks, and thereby create means (functionality) and/or structure for implementing
the functions/acts specified in the block diagrams and/or flowchart block(s).
[0059] These computer program instructions may also be stored in a tangible computer-readable
medium that can direct a computer or other programmable data processing apparatus
to function in a particular manner, such that the instructions stored in the computer-readable
medium produce an article of manufacture including instructions which implement the
functions/acts specified in the block diagrams and/or flowchart block or blocks. Accordingly,
embodiments of present inventive concepts may be embodied in hardware and/or in software
(including firmware, resident software, micro-code, etc.) that runs on a processor
such as a digital signal processor, which may collectively be referred to as "circuitry,"
"a module" or variants thereof.
[0060] It should also be noted that in some alternate implementations, the functions/acts
noted in the blocks may occur out of the order noted in the flowcharts. For example,
two blocks shown in succession may in fact be executed substantially concurrently
or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts
involved. Moreover, the functionality of a given block of the flowcharts and/or block
diagrams may be separated into multiple blocks and/or the functionality of two or
more blocks of the flowcharts and/or block diagrams may be at least partially integrated.
Finally, other blocks may be added/inserted between the blocks that are illustrated,
and/or blocks/operations may be omitted without departing from the scope of inventive
concepts. Moreover, although some of the diagrams include arrows on communication
paths to show a primary direction of communication, it is to be understood that communication
may occur in the opposite direction to the depicted arrows.
[0061] Many variations and modifications can be made to the embodiments without substantially
departing from the principles of the present inventive concepts. All such variations
and modifications are intended to be included herein within the scope of present inventive
concepts. Accordingly, the above disclosed subject matter is to be considered illustrative,
and not restrictive, and the appended examples of embodiments are intended to cover
all such modifications, enhancements, and other embodiments, which fall within the
scope of present inventive concepts. Thus, to the maximum extent allowed by law, the
scope of present inventive concepts are to be determined by the broadest permissible
interpretation of the present disclosure including the following examples of embodiments
and their equivalents, and shall not be restricted or limited by the foregoing detailed
description.
1. A coordination node (110) for controlling communications between Light Fidelity, Li-Fi,
Access Points, APs, (130) and user equipment, UEs, (108), the coordination node (110)
configured to:
receive peer connectivity reports from Li-Fi APs (130) which identify Li-Fi APs having
at least partially overlapping coverage areas;
develop a handover pathway data structure, based on the peer connectivity reports,
that identifies Li-Fi APs (130) that can receive communication handover from other
identified Li-Fi APs (130);
determine an identifier of a first Li-Fi AP (130) providing Li-Fi communication service
for a UE (108);
access the handover pathway data structure using the identifier of the first Li-Fi
AP (130) to determine an identifier of a second Li-Fi AP (130) to which handover from
the first Li-Fi AP (130) can be performed; and
initiate handover of the Li-Fi communication service for the UE (108) from the first
Li-Fi AP (130) to the second Li-Fi AP (130).
2. The coordination node of claim 1 configured to:
determine an identifier of a reporting Li-Fi AP (130) that reported one of the peer
connectivity reports to the coordination node (110);
determine an identifier of one or more observed Li-Fi APs (130) based on content of
the one of the peer connectivity reports; and
store in the handover pathway data structure the identifier of the one or more observed
Li-Fi APs (130) with a logical association to the identifier of the reporting Li-Fi
AP (130).
3. The coordination node of claim 2, further configured to:
receive a report containing a measurement by the UE (108) of a Li-Fi signal received
from the first Li-Fi AP (130);
perform the initiating handover (608, 708) of the Li-Fi communication service for
the UE (108) from the first Li-Fi AP (130) to the second Li-Fi AP (130) responsive
to determining that the measurement does not satisfy a signal quality threshold.
4. The coordination node of claim 2, wherein the one of the peer connectivity reports
contains pairs of an identifier of one of the one or more observed Li-Fi APs (130)
and a measurement by the reporting Li-Fi AP (130) of a Li-Fi signal received from
the one of the one or more observed Li-Fi APs (130), the coordination node being configured
to: selectively perform the storing in the handover pathway data structure the identifier
of the observed Li-Fi AP (130) with a logical association to the identifier of the
reporting Li-Fi AP (130), only if the measurement by the reporting Li-Fi AP (130)
of the Li-Fi signal received from the one of the one or more observed Li-Fi APs (130)
satisfies a signal quality threshold.
5. The coordination node of claim 4, further configured to selectively store the identifier
of the one of the one or more observed Li-Fi APs (130) in the handover pathway data
structure with a logical association to the identifier of the reporting Li-Fi AP (130),
only if a signal strength indicated by the measurement satisfies a signal strength
threshold.
6. The coordination node of claim 4, further configured to selectively store the identifier
of the one of the one or more observed Li-Fi APs (130) in the handover pathway data
structure with a logical association to the identifier of the reporting Li-Fi AP (130),
only if a bit error rate indicated by the measurement satisfies a bit error rate threshold.
7. The coordination node of any one of claims 2 to 6, further configured to:
determine, subsequent to the storing, that an absentee one of the observed Li-Fi APs
(130) has not been identified in a peer connectivity report received from the reporting
Li-Fi AP (130) in at least a threshold elapsed time; and
remove from the handover pathway data structure the identifier of the absentee one
of the observed Li-Fi APs (130) and its logical association to the identifier of the
reporting Li-Fi AP (130).
8. The coordination node of any one of claims 1 to 7, further configured to:
initiate handover of the Li-Fi communication service for the UE (108) from the first
Li-Fi AP (130) to a group of Li-Fi APs (130) at least one of which that is likely
to have a coverage area that includes the UE (108) responsive to an access of the
handover pathway data structure resulting in return of no identifier of another Li-Fi
AP (130) as having been defined as associated with the identifier of the first Li-Fi
AP (130).
9. A system comprising the coordination node (110) of any one of claims 1 to 8 and a
Light Fidelity, Li-Fi, Access Point, AP, (130) for communicating with user equipment,
UEs (108) under control of the coordination node (110), the Li-Fi AP being configured
to:
receive Li-Fi signals from observed Li-Fi APs (130), the Li-Fi signals providing identifiers
of the observed Li-Fi APs (130);
generate a peer connectivity report containing an identifier of the Li-Fi AP (130)
and the identifiers of the observed Li-Fi APs (130); and
report the peer connectivity report to the coordination node (110).
10. The system of claim 9, wherein the Li-Fi AP is further configured to:
receive from a UE (108) measurements by the UE (108) of Li-Fi signals transmitted
by the Li-Fi AP (130) and other Li-Fi APs; and
report an indication of the measurements in the peer connectivity report.
11. The system of claim 9 or 10, wherein the Li-Fi AP is further configured to:
measure a Li-Fi signal received from a UE (108) during Li-Fi communication service
by the Li-Fi AP (130) for the UE (108); and
include an indication of the measurement in the peer connectivity report reported
to the coordination node (110).
12. The system of claim 9, wherein the Li-Fi AP is further configured to:
receive from a UE (108) measurements by the UE (108) of a Li-Fi signal transmitted
by the Li-Fi AP (130); and
send a handover request to the coordination node (110) responsive to the measurement
not satisfying a signal quality threshold.
13. The system of any one of claims 9 to 12, wherein the Li-Fi AP is further configured
to:
measure the Li-Fi signals received from the observed Li-Fi APs (130); and
generate the peer connectivity report to further contain the measurements with defined
associations to the identifiers of the observed Li-Fi APs (130).
14. The system of any one of claims 9 to 13, wherein subsequent to the reporting of the
peer connectivity report to the coordination node (110), the Li-Fi AP is further configured
to:
exclude the one of the observed Li-Fi APs (130) from another peer connectivity report
that is next reported to the coordination node (110) responsive to the determination
that a Li-Fi signal has not been received from one of the observed Li-Fi APs (130)
contained in the peer connectivity report in at least a threshold elapsed time.
15. A method performed by a system comprising a coordination node (110) for controlling
communications between Light Fidelity, Li-Fi, Access Points, APs, (130) and user equipment,
UEs, (108), and a Light Fidelity, Li-Fi, Access Point, AP, (130) for communicating
with user equipment, UEs (108) under control of the coordination node (110), the method
comprising:
receiving, by the Li-Fi AP, (500, 800) Li-Fi signals from observed Li-Fi APs, the
Li-Fi signals providing identifiers of the observed Li-Fi APs;
generating, by the Li-Fi AP, (802) a peer connectivity report containing an identifier
of the Li-Fi AP and the identifiers of the observed Li-Fi APs;
reporting, by the Li-Fi AP, (502, 804) the peer connectivity report to the coordination
node;
receiving, by the coordination node, (502, 700) peer connectivity reports from Li-Fi
APs which identify Li-Fi APs having at least partially overlapping coverage areas;
developing, by the coordination node, (504, 702) a handover pathway data structure,
based on the peer connectivity reports, that identifies Li-Fi APs that can receive
communication handover from other identified Li-Fi APs;
determining, by the coordination node, (604, 704) an identifier of a first Li-Fi AP
providing Li-Fi communication service for a UE;
accessing, by the coordination node, (606, 706) the handover pathway data structure
using the identifier of the first Li-Fi AP to determine an identifier of a second
Li-Fi AP to which handover from the first Li-Fi AP can be performed; and
initiating, by the coordination node, handover (608, 708) of the Li-Fi communication
service for the UE from the first Li-Fi AP to the second Li-Fi AP.